Officers reject claim by Dubai's police chief that they have made secret arrest over murder of Hamas operative in Dubai.

Canadian police have denied claims by Dubai's police chief that a suspect in the assassination of a Hamas leader killed in the emirate in January has been arrested in Canada.

Lieutenant General Dahi Khalfan Tamim said on Tuesday that the arrest of a person over the killing of Mahmoud al-Mabhouh was being covered up by Canadian officials.

Tamim told broadcaster Al-Arabiya that Canada was the location of the arrest. He had previously said only that the arrest was in a Western country.

The police chief also said that Canada had told Dubai, part of the United Arab Emirates (UAE), to keep the arrest secret.

Gilles Michaud, head of National Security Criminal Investigations of the Royal Canadian Mounted Police, told Canada's The National newspaper on Tuesday that he was unaware of any arrest related to the case.

Al-Mabhouh's assassination at a Dubai hotel on January 19 made headlines when Dubai police accused an Israeli hit squad posing as tourists for the killing.

At the time, Israel said of the claims that it maintains a "policy of ambiguity" on intelligence matters.

'Political storm'

Al Jazeera's Dan Nolan, reporting from Dubai, said that the conflicting accounts of the arrest have intensified the increasingly troubled relationship between Canada and the emirate.

"These claims are actually the latest step in what is a political storm between the United Arab Emirates and Canada," said Nolan.

The relationship between the two countries soured over BlackBerry services, with the UAE threatening to suspend services for the Canadian-made device unless its maker, Research in Motion (RIM), complied with the country's telecom laws.

RIM signed a deal this week with the UAE to avoid suspension of services to its users, but tensions between Dubai and Canada have been building over other issues.

"The UAE has been negotiating with Canada to get more landing slots for Emirates airline and Etihad airline ... to allow those airlines to fly more frequently into Canada," said Nolan.

"Soon after that, the UAE reacted by failing to renew a lease which allows the Canadian military to use a base here on Emerati soil as a staging point for their troops who are in Afghanistan," said Nolan.

Calling the tensions between the two countries "an escalating diplomatic and trade war," Nolan also said that a plane carrying Peter McKay, Canada's defence minister, was refused permission to land in the UAE last week.